Electric circuit breaker with overload release



May 31, 1938. GUETT 2,119,459

' ELECTRIC cmcum BREAKER WITH OVBRLOAD-RELEASE Filed April 27, 1956 2 Sheets-Sheet 1 4 INSULATION 58 4 x 5 I I INSULATION \NVENTOR l MONROE GUETT BY HIS ATTORNEYS Patented May 31 1938 UNITED STATES 25 Claims.

This invention relates to snap-acting electric circuit breakers of the type having current responsive means for tripping the breaker to open circuit position upon the occurrence of an overv load in the circuit. More particularly the inoperable snap-acting electric circuit breakers which may be tripped to open position upon the operation of a bimetallic current responsive device.

In certain prior switches of the type to which this invention relates there occurred a time delay between the operation of the thermal overload device and the initial movement of the contact to open circuit position.

It is an object of my invention to provide a circuit breaker of the above type in which actuation of the current responsive means trips the overload mechanism and at once starts moving the movable contact to open circuit position.

Another object of my invention is to provide a circuit breaker of the above type with means independent of the manual snap-acting mechanism, which will cause the contacts to start separating immediately upon actuation of the current responsive device and which will operate whether or not the manual operating means is operative.

Other objects and advantages of my invention will become apparent as it is described in connection with the accompanying drawings.

In the drawings Figure I is a side elevation view, partly in section, of a circuit. breaker embodying the principles of my invention. The parts are shown in closed circuit position.

Figure 2 is a side elevation view of a circuit breaker shown in Figure 1 with the parts in open circuit position, certain of the parts being broken away for the purpose of illustration.

vention relates to manually and automatically Figure 3 is a view similar to Figure 2 but with PATENT OFFICE ELECTRIC CIRCUIT BREAKER WITH OVER- I LOAD RELEASE 1 Monroe Guett, Hartford, Conn., assignor. to The Arrow-Hart & Hegeman Electric Company, Hartford, Conn, a corporation of Connecticut Application April 27,

1936, Serial No. 76,691

mounted in a casing ID of insulating material, the casing preferably being long and narrow and having a wire terminal plate I2 secured to the bottom of the casing at the left end as viewed in Fig. 1. A screw l4, projecting through the bottom of the casing and taking into threaded aperture in the plate, secures it in place. The binding screw I6 is provided in the end of the terminal plate by means of which feed wires may be connected to the breaker. Upon the other end of the terminal plate I2 is mounted a fixed contact button l8 with which cooperates a movable contact button 20 which is mounted upon the end of a movable contact arm 22 of conducting material. This contact arm is mounted upon a pivoted contact carrier designated generally by numeral 24, and is hereinafter more fully described.

At the right end of the casing there is mounted a terminal member 26 stamped from sheet metal in Z-shape. This member is secured to the casing by a bolt 28 passing through the bottom of the casing and taking into the upper horizontal portion of the terminal member. A terminal screw 30 takes into a screw threaded aperture in the lower horizontal portion 26 of the terminal member for the connection of feed wires to the terminal. A lateral extension 32 from the upper horizontal portion of the terminal member 26 is bent upwardly at right angles to that horizontal portion. To this upturned extension 32 an inverted U-shaped bimetallic member 34 has the end of one of its legs riveted or otherwise suit: ably secured. (See Fig. 1.) The end of the other leg of this U-shaped bimetallic member is secured to a conducting angle member 36 by means of a rivet or other suitable means passing through the vertical leg of the angle member. A securing bolt 38 piercing the bottom of the casing takes into the horizontal leg of the member 36 and holds it upon the bottom of the casing. A flexible conductor 40 is electrically connected with the member 36 .by means of a screw 42. This conductor 40 is also connected with the end of contact arm 22 by a screw 44 thus completing the electrical path through the breaker from the terminal 26 through the bimetallic member 34 and its supporting bracket 36, conductor 40, movable contact arm 22 and movable and fixed-contacts 20 and I8 to terminal I2.

The means for moving the contact 20 under normal conditions manually are mounted upon a frame designated generally by the numeral 50. The frame may be stamped from sheet metal providing parallel side plates 50 and 50 which are connected at their left ends as viewed in Figure 5 by a web For supporting the frame upon the casing there are provided at the bottom edges of the side plates 51! and 50 out-turned feet 50 which rest upon protuberances IO from the inside surfaces of the walls of the casing Ill. For manually operating the switch there is provided a hooked shaped lever 52 which is pivotally mounted upon a pivot pin 54 secured in the side plate 50 of the frame. A collar 58 is positioned between the manual lever 52 and the plate 58 to space the lever from the plate and position it centrally in the frame and the casing. A handle 58 of insulating material is molded upon the upper end of the manual lever. Snap-acting means consisting of a coiled tension spring 60 is provided for moving the movable contact with a snap motion during manual operation of the breaker. This spring 60 has its upper end secured to the upper portion of the manual lever directly beneath the handle 58 in any suitable fashion, while the lower end of this spring 60 is secured to the transverse portion of a flat U-shaped member or yoke 62 which is stamped from sheet metal. The ends of the legs of this yoke engage in inverted complementary V-shaped bearing notches 64 which are provided in the side plates 50 and 51'] of the frame.

As the manual lever 52 is moved from the position of Figure l to the position of Figure 2, the line of action of the spring 60 passes through the plane of the yoke 62 and causes the yoke to move from its engagement with one side of the V-notches into engagement with the other side with a snap motion. A reverse action takes place in the movement of the leverv from the Figure 2 position to the position shown in Figure 1.

In order to transmit the motion of the yoke 62 to the movable contact a pair of identical triangular arms 66 and 6B are secured to the legs of the yoke 62 by means of outward extensions of the legs of. the yoke passing through complementary apertures in the arms. These extensions are peened over to make a permanent connection between the yoke 62 and the arms 66 and 66*, with the arms in parallel planes perpendicular to the plane of the yoke.

Connected to the ends of the arms 56 and 68 by a pivot pin 68 is one of a pair of toggle link members designated generally by the numerals 10 and 12 as best illustrated in Figure 6. These links are metal stampings of irregular shape as may be observed by a study of Figure 6. L nk 10 has parallel side arms Ill and 10b which are joined by a cross bar 70, the arm Ill having a large lateral semi-circular extension at one end. The link 12 has parallel arms '12 and 12 which are joined by a cross bar 72, the arm l2 having a large lateral semi-circular extension at one end. The links 10 and 12 are pivoted together by a pin 14 passing transversely through the side arms of the links concentrically with the semicircular extensions. The link 12 is pivotally connected with the contact carrier 24 by a pin.'l8 transversely extending thru the end spaced from pin 14. The contact carrier 24 is a U-shaped metal stamping having side plates 24 and 24 parallel to but within the arms of the link 12. The side plates are connected by a transverse web portion 24. The transverse web portion 240 has mounted on it the movable contact arm 22 by a screw or other suitable means. The carrier 24 is pivotally mounted by means of a pivot pin transversely extending thru the ends of a pair free ends of the overload yoke 90.

of horizontally extending, vertically parallel arms 82 and 82 of a supporting bracket designated generally by numeral 82. This pivot 80 is fixed with relation to the casing. A horizontal web 82 joins the edges of arms 82 and 82 at the ends away from pivot 80, and affords means to mount the bracket 82 on the angle bracket 36. The terminal screw 42 serves the double purpose of attaching the conductor 40 and the supporting bracket 82 to the angle bracket 36.

. It may now be observed that as the yoke 62 moves from right toleft, that is from the position of Figure 1 to the position of Figure 2 in response to the movement of the handle 58, the arms 66 will rock in a'clockwise direction about the axis of the yoke 62. This will carry the toggle links 10 and 12 while in their straightened condition in an upward direction thereby exerting clockwise pull upon the contact carrier 24 about its pivot 80 thus causing the movable contact 20 to separate from the fixed contact 18. Upon reverse movement of the handle back to the position of Figure 1 the arms 66 will move counterclockwise forcing the toggle links 10 and 12 downwardly and turning the contact carrier 24 counterclockwise about its pivot 80 thereby engaging the contact 20 with the contact l8.

In order to keep the toggle links in straightened condition they are mounted with the arm 12 against the inside of arm (0 and with the arm I2 against the outside surface of the arm 10, and small circular protuberances H and 13 are pressed out from the inner faces of the enlarged semi-circular portion of the arm 12 in positions spaced approximately apart, one of these protuberances (1|) being at the end farthest removed from the pivot pin 18. These protuberances may engage in a complementary indentation IT in the'middle of arm 10 In order to keep the arms 10 and 12 and T0 and .12 pressed against each other a compression spring 15 is wound around the pivot pin 14, and has its opposite ends pressing against the arm I2 and the arm 10 Movement of the toggle links beyond straightened position is prevented by the engagement of the edges of the cross bars HI and 12 as may best be observed from Figures 2 and 4.

In order to cause tripping of the breaker upon occurrence of an overload there is provided an overload member or a yoke designated generally by the numeral 90. This yoke is symmetrical having identical side plates, in the form illustrated in Figure l which are joined by a transverse portion 90 at their right ends. The over load yoke 90 is pivotally mounted by a pin 92 upon a supporting bracket designated generally by the numeral 94. The supporting bracket 94 is a sheet metal stamping comprising a strip of metal as wide as the web 50 of the frame 50, the strip being bent into a right angle providing a vertical portion 94 riveted against the web 50 and a horizontal portion 94 having a pair of opposite lateral extensions bent up to form parallel vertical mounting lugs 94 and 94 The pivot pin 92 passes thru these lugs and thru the A torsion spring 95 is wound around the pivot 92 and tends to rotate the overload yoke 90 in counterclockwise direction as the device is viewed in Figures 1, 2 and 3. This tendency is resisted by a catch 90 which is rigidly secured to the center of the transverse portion 91.! of the overload yoke 90 and extends at right angles thereto. The catch 90 engages with the edge of a catch plate .34

out the toggle links Ill and I2.

which is secured to the transverse portion of the bimetallic element 34 and is suitably insulated therefrom.

In order that counterclockwise movement of the overload lever 98 may be transmitted to the contact carrier 24, the upper ends of a pair of identical links 96 are connected to the side plates of the overload member 90 at points in the midportio'ns of those plates. The lower ends of the links are pivotally connected to the contact carrier 24 by a pin 98 passing through the lower ends of the links 96 and through the side Plates 24 and 24 of the contact carrier. Inclined slots 24 are provided in the plates 2! and 24 in which the pin 98 works. Normally the pin 98 will be very close to the upper end of the slot so that at the instant the bimetallic member 34 flexes to the right (see Figure 3) upon the occurrence of overload and releases the overload member 90, the motion of the overload member will be transmitted through the links 96 to the carrier 24. 'When the pin 98 is in its normal closed circuit position in the upper end of the slot 24 a tripping finger 1.2% which extends laterally from the arm 12*, lies on top of the pin 98 so that before the pin 98 engages the upper end of the slot it rotates the finger l2 and toggle lever 12 counterclockwise to break the toggle. Thus when the pin 98 engages the upper end of the slot the contact carriage 24 is free to pivot to open circuit position.

It should be observed that during manual operation of the switch the toggle is over-set and the action of the arms 66 and 66' will tend to keep the toggle in over-set or straightened position.

In order to reset the device after it has been tripped by an overload, the handle is moved from on position, as shown in Figure 3, to the "oiT position shown in Figure 2 and a pair of cylindrical bearing cams I 9.0, which project perpendicularly from the hand lever 52' beneath the handle 58 engage with inclined or cam surfaces 90 of the overload member 90 to depress the c'fi/erload member or-move it inclockwise direction until the catch 90 engages with the edge of catch plate 34 of the bimetallic member again. During this movement the line of action of the spring 60 will have moved through dead-center position and caused the yoke 62 to move to the position of Figure 2 thereby moving the arms 68 and 66 to open circuit position and straightening From the foregoing it will be observed that I have provided a switch in which the overload tripping mechanism is independent in its action of the manual operating means and will operate whether or not the manual operating means becomes stuck or inoperative. At the same time I have provided overload tripping means which operates to break the toggle and to start separating movement of the contacts with one movement when the current responsive element moves to release the overload operating mechanism.

Many modifications within the scope of my invention will occur to those skilled in the, art, therefore I do not l mit myself to the specific embodiment of the invention illustrated and described.

I claim 1. In an overload circuit breaker, a fixed contact, a movable contact mounted for movement about a fixed pivot, manually controlled snapping mechanism including a spring for operating said movable contact, overload mechanism for causing movement of said movable contact with a snap,

said overload mechanism being operable while said manual snapping spring remains stationary.

2. In an overload circuit breaker, a fixed contact, a movable contact mounted for movement about a fixed pivot, manually controlled snapping means for operating said movable contact, overload operating means for causing separating movement of said contacts with a snap, a collapsible connection between said manual means and said movable contact, means for collapsing said connection upon operation of said overload means, means maintaining said connection in operative condition while the breaker is being manually operated, a lost motion connection between said movable contact and said overload snapping means. permitting movement of said manual snapping means while said overload means remains stationary.

3. In an overload circuit breaker, a fixed contact, a movable contact mounted for movement about a fixed piv ot, manually controlled snapping means for operating said movable contact, overload operating means for causing separating movement of said contacts with.a snap, connecting means between said manual snapping means and said movable contact permitting movement of said overload means while said manual snapping means remains stationary.

4. In an overload circuit breaker, a fixed contact, To), movable contact mounted for movement about a fixed pivot, manually controlled snapping means for operating said movable contact, overload operating means for causing separating movement of said contacts with a snap, connecting means between said overload snapping means and said movable contact permitting movement of said manual snapping means while said overload snapping means remains stationary, and connecting means between said manual snapping means and said movable contact permitting movement of said overload snapping means while said manual snapping means remains stationary.

5. In an overload circuit breaker, a fixed contact, a movable contact mounted for movement about a fixed pivot, manually controlled snapping means for operating said movable contact, overload operating means for causing separating movement of said contacts with a snap, a lost motion connection between said overload snapping means and said movable contact permitting op eration of the movable contact by said manual snapping means while said overload snapping means remains stationary, and connecting means between said manual snapping means and said movable contact permitting operation of the movable contact by said overload snapping means while said manual snapping means remains stationary.

6. In an overload circuit breaker, a fixed contact, a movable contact mounted for movement about a fixed pivot, manually controlled snapping means for operating said movable contact, overload operating means ior causing separating movement of said contacts with a snap, connecting means between said overload snapping means and said movable contact permitting operation of the movable contact by said manual snapping means while said overload snapping means remains stationary, 'anda collapsible connection between said manual snapping means and said movable contact permitting operation of said movable contact by said overload snapping means while said manual snapping means remains stationary.

'7. In an overload circuit breaker, a fixed contact, a movable contact mounted for movement about a fixed pivot, manually controlled snapping means for operating said movable contact, overload operating means for causing separating movement of said contacts with a snap, a lost motion connection between said overload snapping means and said movable contact permitting operation of the movable contact by said manual snapping means while said overload snapping means remains stationary, and a collapsible connection between said manual snapping means and said movable contact permitting operation of said movable contact by said overload snapping means while said manual snapping means remains stationary.

'8. In an overload circuit breaker, a fixed contact, a movable contact mounted for movement about a fixed pivot, manually controlled overcenter spring means for snapping said movable contact into and out of engagement with said fixed contact, overload operating means biased to, circuit opening position, connecting means between said manual snapping means and said movable contact permitting movement of said overload means while said manual snapping means remains stationary.

9. In an overload circuit breaker, a fixed contact, a movable contact mounted for movement about a fixed pivot, manually ,controlled overcenter spring means for snapping said movable contact into and out of engagement with said fixed contact, overload operating means biased to circuit opening position, connecting means between said overload snapping means and said movable contact permitting movement of said manual snapping means while said overload snapping means remains stationary, and connecting means between said manual snapping means and said movable contact permitting movement of said overload snapping means while said manual snapping means remains stationary.

10. In an overload circuit breaker, a fixed contact, a movable contact mounted for movement about a fixed pivot, manually controlled overcenter spring means for snapping said movable Contact into and out of engagement with said fixed contact, overload operating means biased to I circuit opening position, a lost-motion connection between saidoverload snapping means and said movable contact permitting operation of the movable contact by said manual snapping means while said overload snapping means remains stationary, and connecting means between said manual snapping means and said movable contact permitting operation of the movable contact by said overload snapping means while said manual snapping means remains stationary.

11. In an overload circuit breaker, a fixed contact, a movable contact mounted for movement about a fixed pivot, manually controlled overcenter spring means for snapping said movable contact into and out of engagement with said fixed contact, overload operating means biased to circuit opening position, connecting means between said overload snapping means and said movable contact permitting operation of the movable contact by said manual snapping means while said overload snapping means remains stationary, and a collapsible connection between said manual snapping means and said movable contact permitting operation of said movable contact by said overload snapping means while said manual snapping means remains stationary.

12. In an overload circuit breaker, a fixed contact, a movable contact mounted for movement about a fixed pivot, manually controlled overcenter spring means for snapping said movable contact into and out of engagement with said fixed contact, overload operating means biased to circuit opening position, a lost motion connection between said overload snapping means and said movable contact permitting operation of the movable contact by said manual snapping means while said overload snapping means remains stationary, and a collapsible connection between said manual snapping means and said movable contact permitting operation of said movable contact by said overload snapping means while said manual snapping means remains stationary.

13. In an overload circuit breaker, a fixedcontact, a movable contact mounted for movement about a fixed pivot, manually controlled overcenter spring means for snapping said movable contact into and out of engagement with said fixed contact, overload operating means biased to circuit opening position, a collapsible connection between said manual snapping means and said movable contact, means for collapsing said connection and simultaneously separating said movable contact from said fixed contact by the initial movement of said overload means.

14. In an overload circuit breaker, a fixed contact, a movable contact mounted for movement about a fixed pivot, manually controlled overcenter spring means for snapping said movable contact into and out of engagement with said fixed contact, overload operating means biased to circuit opening position, a collapsible connection between said manual snapping means and said movable contact, means for collapsing said connection and simultaneously separating said movable contact from said fixed contact by the initial movement of said overload means and means to maintain said collapsible connection in operative condition during manual operation of the breaker.

15. In an overload circuit breaker, a fixed contact, a movable contact mounted for movement about a fixed pivot, manually controlled overcenter spring means for snapping said movable contact into and out of engagement with said fixed contact, overload releasable means biased to circuit opening position, current responsive means restraining the bias of said overload means, a collapsible connection between said manual snapping means and said movable contact, means to collapse said connection and separate said movable contact from said fixed contact by the movement of said overload releasable means.

16. In an overload circuit breaker, a fixed contact, a movable contact mounted for movement about a fixed pivot, manually controlled overcenter spring means for snapping said movable contact into and out of engagement with said fixed contact, overload releasable means biased to circuit opening position, current responsive means restraining the bias of said overload means, a collapsible connection between said manual snapping means and said movable contact, means to collapse said connection and separate said movable contact from said fixed contact by the movement of said overload releasable means and means to maintain said collapsible connection in operative condition during manual operation of the breaker.

1'7. In a circuit breaker, a fixed contact and a movable contact engaged therewith, a manual operating lever, pivotal contact actuating means including an over-center spring movable by said lever to operate said movable contact with a snap, in combination with an overload lever pivotally connected with said movable contact and biased to open circuit position, current responsive means holding said overload lever against said bias, and a spring providing said bias of said overload lever and causing said overload lever and movable contact to move to open circuit position on the occurrence of an overload without the necessity of movement of said overcenter spring.

18. In a circuit breaker, a fixed contact and a movable contact engaged therewith, a manual operating lever, pivotal contact actuating means including an over-center spring movable by said lever to operate said movable contact with a snap, in combination with an overload lever pivotally connected with said movable contact and biased to open circuit position, current responsive means holding said overload lever against said bias, said overload lever starting open-circuit movement of said movable contact with its own open circuit movement upon release by said current-responsive means.

19. In a circuit breaker, a fixed contact, and a movable contact engaged therewith, a manual operating lever, pivotal contact actuating means including an over-center spring movable by said lever to operate said movable contact with a snap, in combination with an overload lever mounted on a fixed pivot and having a movable pivotal connection with said movable contact, a second spring biasing said overload lever to open circuit position and causing said lever and movable contact to move to open circuit position upon the occurrence of an overload without the necessity of movement of said over-center spring, and current-responsive means holding said overload lever against said bias.

20. In a circuit breaker, fixed and movable contacts, manual operating means for moving said movable contact to open circuit position with a snap, overload operating means separate from said manual means for moving said movable contact to open circuit position with a snap on overload, said overload means including a lever pivoted about a fixed pivot and having a movable pivotal connection with said movable contact, and means biasing said overload lever to open circuit position.

21. In a circuit breaker, fixed and movable contacts, manual operating means for moving said movable contact to open circuit position with I a snap, overload operating means separate from said manual means for moving said movable contact to open circuit position with a snap on overload, said overload means including a lever pivoted about a fixed pivot and having a movable pivotal connection with said movable contact, means biasing said overload lever to open circuit position independently of said manual operating means.

22. In a circuit breaker, fixed and movable contacts, manual operating means for moving said movable contact into open circuit position with a snap, overload operating means for moving said movable contact to open circuit position with a snap independent of said manual operating means, said manual and overload operating 'means having separate springs urging said contacts apart, said manual and said overload operating means having separate pivotal connections with said movable contact.

23. In a circuit breaker, fixed and movable contacts, manual operating means for moving said movable contact into open circuit position with a snap, overload operating means for moving said movable contact to open circuit position with a snap independent of said manual operating means, said manual and overload operating means having separate springs urging said contacts apart, said overload operating means including a lever having a pivotal connection with said movable contact, said movable contact hav ing a separate pivotal connection with said manual operating means.

24. In a circuit breaker, fixed and movable contacts, manual operating means for moving said movable contact between open and closed circuit positions, overload operating means separate from said manual means for moving said movable contact to open circuit position with a snap on overload, said overload means including a lever pivoted about a fixed pivot and having a movable pivotal connection with said movable contact and means biasing said overload lever to open circuit position.

25. In a circuit breaker, fixed and movable contacts, manual operating means for moving said movable contact between open and closed circuit positions, overload operating means separate from said manual means for moving said movable contact to open circuit position with a snap on overload, said overload means including a lever pivoted about a fixed pivot and having a movable pivotal connection with said movable contact and means biasing said overload lever to open circuit position independently of said manual operating means.

MONROE GUE'I'I. 

